Aim: In this study, it was aimed an experimental model of
acute and chronic copper toxicity in the form of rainbow
trout with copper sulfate pentahydrate and investigate the
clinic, macroscopic and microscopic findings.

Materials and Methods: In the present study, thirty rainbow
trout were divided into four groups: Two experiment
[(Acute Group (Group I), n:10 - Chronic Group (Group III),
n:10)] and two control groups [(Acute Control Group (Group
II), n:5 - Chronic Control Group (Group IV), n:5)]. Copper
sulphate pentahidrate was given 2 mg/L for a 5 days and 0.5
mg/L for a 21 days in Group I and III, respectively.

Results: Macroscopically, livers were swollen and had dark
red color in Group I. Gills were oedematous. In Group III, liver
had remarkable pale color. Gill were pale and skin was covered
by mucous. In Group I, the most salient microscopic finding
was seen in the liver. Degenerations were seen widely in
hepatocytes. In the gills, epithelial necrotic changes with vascular
lesions including edema, hyperemia and hemorrhage
were observed. In the kidney, there were degeneration and
eosinophilic hyalin droblets with variable sized in the cytoplasm
of tubular epitheliums. Liver had diffusive degenerations
in Group III. Hepatocyte nucleus has remarkable vesicular
appearance in all findings. There was obvious thickness
caused by hyperplasia in the gills. There was an increase in
the number of mucous cell and hydropic degeneration on
epithelial cells in the epidermis of the skin.

Conclusion: As a result, it is recommended to consider the
concentration of copper sulfate pentahydrate in water in rainbow
trout aquaculture.